The Mustang began to be widely recognized as the performance leader of cars in 1969. Therefore, Ford made some major changes to enhance the Mustang further. Much restyling was done to the 1969 Mustang. This was the second complete restyling done since 1964. It was given about 3.8 inches to its length which happen to all be on the front of the car. 140 pounds in curb weight was added as a result. The car was made larger while the height was taken down one and a half inches. The features of the '69 Mustang were the sharp nose with a simpler grille that highlighted the Mustang running horse showpiece, four headlights, and the correction of the fake side scoops on the coupes and convertibles. More options available to this year meant major changes and new engines. Ford made available a total amount of 10 different engines to choose from to put in the Mustang. Under the hood and the exterior were not the only things being altered. The inside received the major change of the dashboard being separated into two boxy openings. All these new changes grabbed the attention of all car enthusiasts that loved performance, look, and speed. However, Shelby Mustangs could still be bought, but all the attention was now directed toward the Mach 1 and Boss Mustangs produced by Ford. The Shelby line of cars were not looked at as superior as they had been.

In '69, the Mach 1 body style was unveiled. It came standard with a 351 cid V8 or could be ordered with the 428 Cobra Jet. It now came in three conditions of adjustment. The two that were added were the non-Ram Air version and the Ram-Air version that breathed through a shaker hood scoop. The Super Cobra Jet engine surpassed the list and was included with the Drag Pack option. With a modified crankshaft, stronger connecting rods, and the shaker hood, the new Super Cobra Jet was an option more popular than others. A limited-slip 3.91:1 or 4.30:1 rear axels came in the Drag Pack, but air conditioning did not. These cars were built for only straight ¼ mile lines and not for curves. The engines were rated too low at just 335 horse power. There was so much power at the rear tires, it suffered 59/41% front/rear bias and damaged handling.

Another new style, the Boss series, was debuted in '69 also. The Boss received its name from the stylist Larry Shinoda's nickname for Semon, the Ford president, which was "Bunkie" Knudson. The Boss Mustangs were built for the circle tracks and to qualify the 429 V8 for NASCAR. These Mustangs had a Boss 429 package option that came with a 429 cid V8 made for the race tracks. Also included were header type exhaust manifolds and an aluminum high riser. The options that came with all of the Boss models included the four speed manual, a 3.91:1 Traction-Lok axle, an oil cooler, race suspension, a trunk mounted battery, and the finest interior that came with the Mustang yet. These Boss 429's were astonishing until they were drove on the streets. They depended on high revs which damaged their starts on the streets, and the original models first sent out received inaccurate valve springs that stopped winding at 4500 rpm instead of 6000 rpm. Regardless, the Boss 429's had amazing handling. To oppose Chevrolet's Camaro Z/28 in the Trans Am racing, Ford built another Boss mode. The Boss 302 used a 302 cid V8 which received the cylinder heads from the racing 351 cid engine. The 302 could come with the shaker hood scoop and was underrated at the equivalent of the Camaro Z/28's engine at 290 horse power.

All car enthusiasts loved the Mustang. It was a car built for speed and performance, which made it stand out over others. Also, there has never been a focus on making the Mustang into an exotic car. Even the very popular Boss 429's, as well as other common vehicles, were assembled in factories with unselective precision by a UAW workforce where parts were continually being rushed along the line. There, the Mustangs parts were shared in common with the six-cylinder Falcons, four-door Fairlanes, and bare Galaxies. Detailed craftsmanship has always been on the backburner with the Ford Mustang. Regardless, it still is extremely pleasing to look at, obviously still satisfies several individuals, and is made affordable to most.